US4923565A
Expired / Lapsed
US
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Method for treating a paper pulp with an enzyme solution
Assignee: Cellulose du Pin SA
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Filing: 1987-09-22
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Granted: 1990-05-08
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Expires: 2007-09-22
Abstract
Abstract An enzyme preparation containing cellulases and/or hemicellulases is reacted on a homogeneous aqueous suspension of paper pulp having a Schopper-Riegler (SR) degree determined in accordance with standard NFQ 50 003 of at least equal to 25. A paper pulp based on recycled fibers is treated.
Inventors
- 👤 Jean-Luc Fuentes
- 👤 Michel Robert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:17
CPC Classifications
D; D21; D21C; D21C5/00; D21C5/005
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
125 words
A method for treating a papermaking pulp with an enzyme preparation, comprising treating a homogeneous aqueous suspension of said papermaking pulp having a Schopper-Riegler degree (SR) determined in accordance with standard NFQ 50 003 of at least equal to 25 prior to treatment with an enzyme preparation introduced at a concentration of 0.01% to 2% by weight in relation to the total weight of dry papermaking pulp, with the indicated percentages corresponding to an enzyme preparation in powder form having a C 1 activity (highly pure microcrystalline cellulose) of 0.168 USI/mg of powder, a C x activity (carboxymethylcellulose) of 3.91 USI/mg of powder and a xylanase activity of 31 USI/mg of powder, to obtain a lowering of the SR degree and improve the suspension's drainability.
Claim 2
Independent Claim
125 words
A method for treating a papermaking pulp with an enzyme preparation, comprising treating a homogeneous aqueous suspension of said papermaking pulp having a Schopper-Riegler degree (SR) determined in accordance with standard NFQ 50 003 of at least equal to 25 prior to treatment with an enzyme preparation introduced at a concentration of 0.01% to 2% by weight in relation to the total weight of dry papermaking pulp, with the indicated percentages corresponding to an enzyme preparation in powder form having a C 1 activity (highly pure microcrystalline cellulose) of 0.168 USI/mg of powder, a C x activity (carboxymethylcellulose) of 3.91 USI/mg of powder and a xylanase activity of 31 USI/mg of powder, to obtain a lowering of the SR degree and improve the suspension's drainability.
Claim 3
Dependent Claim
28 words
The method in accordance with claim 1, wherein the concentration of the enzyme preparation is 0.1% by weight in relation to the total weight of dry papermaking pulp.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-07 | 1993-11-06 | 1994-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-07 | 1997-11-06 | 1998-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-07 | 2001-11-06 | 2002-05-08 | $7700.00 | Window Closed / Lapsed |